"Lastly, women listen," O'Leary says.
"Who are you serving when you're running a business? Number one your customers, number two your employees and number three your shareholders," O'Leary says, and to succeed, executives need to listen to everyone. That's something women excel at, especially with critical feedback.
"They listen to all of them, they take the advice, they take the information and they pivot," O'Leary says. "Understanding when you're going in the wrong direction is the tell of a great entrepreneur. Women are very good at listening, assimilating and redirecting, and that's how you make it in business."
Of course, women entrepreneurs still encounter many obstacles.
Among the firms doling out venture capital funding — the main avenue for start-ups to get money — women represent 11 percent of decision makers, according to a the most recent 2016 report from the National Venture Capital Association (NVCA) and Deloitte.
And only 12 percent of venture capital dollars go to founding teams with at least one female member, according to data provided to CNBC Make It by PitchBook, which studies market data.
But for O'Leary, investing in women-built businesses has been a key to success.
"I can't express how much I'm inspired by the business women I've had the pleasure of partnering with on ['Shark Tank']," O'Leary tweeted on International Women's Day March 8. "They impress me more every day with their innovation, strength, and tenacity!"
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